How Does Sleep Impact Our Gut Health?

Most of us are aware that certain foods, drinks, stress and even exercise can impact our gut health, but did you know that how and when we sleep also takes its toll on our digestive system…?

This month and in theme for world sleep day on the 18th of March, I am shining the light on how a good night’s slumber can keep your gut bugs happy and sharing six healthy habits that may help to encourage a better night’s sleep. 





When we are sleep deprived, our appetites can go through the roof – am I right? 

This is partly thanks to a surge in our hunger hormones that can result in feeling ravenous all day long. So…there is a biological reason you want that pizza, the extra chocolate bar, burgers (or them all in one go) over your daily quinoa salad after a poor night’s sleep. And whilst this occasional change in food choices is unlikely to impact your gut, if this way of eating becomes habitual it may begin to impact your gut health. One study demonstrated that individuals who sleep earlier, have better blood sugar control after their breakfast the next morning. Whilst those that sleep later or have disrupted sleeping patterns may have worse control when it comes to blood glucose regulation. These blood sugar peaks and drops may increase appetite and increase cravings for more processed foods.(3)

This pattern of eating may impact your gut health, thanks to the fact that foods high in sugar, saturated fat and processed foods have been linked to reduced gut diversity. (2) 



A lack of sleep can impact the release of our stress hormone cortisol, and too much of this hormone puts our bodies into a fight or flight response. When we are in this stressed state, our digestive system shuts down, and we are no longer able to digest in the same way as when we are relaxed. In addition, stress impacts our gut motility, which when not performing optimally can lead to constipation and bloating. 

And if that wasn’t enough to convince you to optimise your sleep, a surge of stress hormones may have the potential to result in hyper-intestinal permeability, also known as leaky gut, where food and toxins can pass through the intestine into the bloodstream causing further inflammation. 



When we sleep, our bodies focus on housekeeping tasks, and one of those is digestion. 

Eating too close to bedtime may trigger digestive symptoms and impact the body’s MMC – our migrating motor complex that helps to clear out the digestive tract.

In addition, when our body is busy digesting, it isn’t able to fully relax and may impact your ability to enter deep modes of restorative sleep. 



Sleep deprivation can impact neurochemicals such as serotonin (our happy hormone) and melatonin (our sleepy hormone). Serotonin production is impacted by our circadian rhythm as well as exposure to natural light. With 95% of serotonin being produced in the digestive system,  it makes sense that when our circadian rhythm is disrupted, our serotonin production may be too. 

Serotonin plays a key role in bowel movements and pain sensitivity. As poor sleep can impact the balance of melatonin and serotonin, it may also impact other digestive functions such as bowel regularity.



As we have seen above, the quality of your sleep is fundamental for good gut health and microbiome diversity.  A greater microbiome diversity and good strains of bacteria in the gut have been associated with better sleep, whilst bad strains of bacteria have been linked to poor quality sleep.

One study (on mice) suggested that diet alterations to encourage the growth of good gut microbes may have the potential to help those who have sleep difficulties. This research is built on previous work stating that elements of cognition and brain development have a strong association with intestinal microbial health and metabolism. (4)

Overall, If you’ve had one or two nights of restless sleep, don’t ring the alarm bell just yet. However, the longer you are sleep deprived, the more likely it is that it could lead to blood sugar dysregulation issues, with the bigger impact it will have on your gut health. 




 It’s important to prioritise and create enough space in your day for sleep. Think of sleep as an investment for your overall health and well-being. A lack of sleep may not only impact your gut health but over a long period of time can lead to weight gain, lowered mood, reduced immune system function and more… Aim for 7-9 hours of good quality sleep a night.



Our natural sleep cycle follows the daily light-dark shift, and getting too much light exposure in the evening can actually make it harder to get enough sleep. One of these light sources comes from blue lights emitted by technology. To avoid this exposure, download blue light blocking apps on your phone and laptop and consider wearing blue light blocking glasses when watching TV – My favourite glasses are the Ocushield glasses, and you can follow my link for 10% off.



On a further note from the above, bright light at night might keep us up, but on the other hand, not enough natural light in the day can affect our sleep patterns too. Natural light prompts our cortisol awakening response which helps us wake up and stay energised – without it, we can feel sleepy and drowsy all day. Aim for natural light exposure in the first half of the day to support this energy production. Have your morning tea or coffee sat by a large open window or outside, or consider a lunchtime walk.



Stress management is unique to each person, but if you notice stress is keeping you up at night, it might be worth investing in some de-stressing activities. Consider trying some meditation or deep breathing exercises to wind down before bed. One of my favourites is the CALM app bedtime stories.



Certain foods can hinder our ability to fall asleep, whilst others can help to promote melatonin production and relaxation.

    1. Avoid caffeine too late in the day as this can impact our stress hormone release – remember that dark chocolate also contains caffeine!
    2. Keep alcohol to 3 hours before bed as the breakdown of alcohol in the liver can impact our ability to enter deep sleep and REM cycles
    3. Consider sleep-promoting teas such as Tulsi, Chamomile and sleep blends. My favourite is Pukka Organic Night Time Tea.
    4. Tart cherries are the world’s richest source of melatonin. Consider a tart cherry extract a few hours before bed. My go to option is CherryActive cherry active concentrate



A bedtime routine can help many of us get in the mood and ready for deep, quality sleep. However, it doesn’t need to be long-winded or complex. Whether you enjoy lighting a candle, having a 20-minute bath or making a cup of herbal tea in the evening, these can all become part of a bedtime routine. Begin with one thing that you know promotes relaxation and incorporate more as you begin to reap the rewards of self-care!


* Please check in with your healthcare provider before taking any supplements or herbs especially if pregnant, breastfeeding or taking medication




https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0201829 (1) 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7284805/ (2) 

https://link.springer.com/article/10.1007/s00125-021-05608-y (3)

https://www.nature.com/articles/s41598-020-76562-9 (4)

Please note, Clarissa Lenherr Nutrition Limited uses affiliate links. If you buy something using these links, we may earn an affiliate commission, at no additional cost to you.

Leave a Comment

Hi there

London Nutritionist Clarissa Lenherr

I’m Clarissa, a registered nutritionist (mBANT) and workplace wellness expert. In my practice, I have helped hundreds of clients reach optimal health through creating sustainable, effective habits and dietary adjustments. My aim is to empower people with the skills, tools and knowledge to take their health into their own hands and feel the happiest, healthiest versions of themselves. Featured in The Daily Mail, Women’s Health, The Telegraph, and more.




Sign up for my exclusive 'Happy Gut Health' Ebook with recipes, expert advice and latest news.